MG Car Repair: that new mg, air gap, check connections

Question
Thanks so much for your previous help!  Now I seem to have an ignition issue on my early 1978 mgb.  The distributor is an electronic, factory(though I think it was retrofitted in the early eighties), advance unit and it has that amplifier box mounted under the coil. The car inexplicably started to quit intermittently - yes the tack drops off in the middle of the highway etc...then restarts later like nothing happened.  If I keep the starter cranked, it will fire up but stops as soon as I back off the key. Is that the 12 amp start circuit overriding the faulty 3-6 amp run circuit?  I am confused which electronic ignition part to replace - or how to accurately test since the problem doesn't surface in a predictable pattern. ARGH!!! Thanks for any light on this!

Answer
Hi Dan,
Not much you can do with most aftermarket electric ignition systems. If you test the coil and check connections, check the air gap then it either works or it doesn't work. This is one of the bad points of an electronic ignition over a Kettering ignition (points). That is true that you need to test while in the failed mode.
Howard